1. Field of Invention
The present invention concerns a light conductor.
2. Description of the Related Art
The present invention relates to a light conductor. Such a light conductor is known from published German patent application DE 199 25 363 A1 and consists of an input coupler arranged so that divergent incident light is coupled into the inside of the light conductor in such a way that the coupled in light inside the light conductor is distributed into a first layer, parallel layers, and second layers, whereby each second layer is spanned by a normal of the first layer and by a line located in the first layer. Further, the known light conductor includes a ribbon-shaped light emitting area.
Divergence refers to the diverging of light beams. A divergent beam is a light beam which has an opening angle diverging from zero. A parallel light beam could be allocated to an opening angle of zero.
The light conductor known in the art is plate-shaped and consists of extended boundary areas (which are parallel to each other) and narrow side areas (which connect the plate-shaped boundary areas to each other).
The first layers are parallel to the extended boundary areas, which can also be described as broadsides of the plate-shaped light conductor. The second layers are perpendicular to it in the light conductor in such a way that the light rays inside the light conductor run within such second layers; these are imaginary layers whose location is defined by the direction of the light rays inside the light conductor. The ribbon-shaped light emitting area is located in a narrow side of the known plate-shaped light conductor.
In order to achieve a parallel light distribution in the light conductor in the direction towards the light emitting area, the light known in the art is designed such that the narrow side of the plate-shaped light conductor opposite of the ribbon-shaped light emitting side is arranged in the form of a reflector, which consists of parabolic contours in the first layers (or the areas parallel to the extended plate-shaped areas and perpendicular to this a prism-like contour) which redirects incident light twice. Thus, the reflector directs the divergent incident light as parallel light towards the ribbon-shaped light emitting area opposite the reflector.
A significant disadvantage of the light conductor known in the art is that radial emitted light (which reached directly into the half space facing the light emitting area) does not reach the reflector and is thus not parallelized. Yet, with respect to lighting equipment of motor vehicles (such as head light functions or signal light functions), a light emitting area that is as parallel as possible and shining as homogeneous (equally bright) as possible is desired. Such light has the advantage that it can be easily distributed into government regulated light distributions by subsequent optics. From an artistic point of view, a light conductor is further desired which features a ribbon-shaped light emitting area with a large ratio between the length of the light emitting area and its width and which fulfills these requirements (homogeneity, parallelism).